How to validate the date such that it is after today in Rails?

Question

I have an Active Record model that contains attributes: expiry_date. How do I go about validating it such that it is after today(present date at that time)? I am totally new to

Answer 1

I took @dankohn answer, and updated to be I18n ready. I also removed the blank test, because that's not the responsibility of this validator, and can easily be enabled by adding presence: true to the validates call.

The updated class, now named in_future, which I think is nicer than not_in_past

class InFutureValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    record.errors.add(attribute, (options[:message] || :in_future)) unless in_future?(value)
  end

  def in_future?(date)
    date.present? && date > Time.zone.today
  end
end

Now add the in_future key to your localization file.

For all fields under errors.messages.in_future, e.g. for Dutch:

nl:
  errors:
    messages:
      in_future: 'moet in de toekomst zijn'

Or per field under activerecord.errors.models.MODEL.attributes.FIELD.in_future, e.g. for the end_date in a Vacancy model in Dutch:

nl:
  activerecord:
    errors:
      models:
        vacancy:
          attributes:
            end_date:
              in_future: 'moet in de toekomst zijn'